External liquefaction device

Abstract

The utility model discloses an external liquefaction device which comprises a cold insulation box, a liquid air energy storage system used for generating liquid air, a nitrogen heat exchanger and an oxygen heat exchanger, the nitrogen heat exchanger and the oxygen heat exchanger are arranged in the cold insulation box, a cold source pipe set is installed on the nitrogen heat exchanger, the nitrogen heat exchanger is connected with a nitrogen heat exchange pipe set, and the nitrogen heat exchange pipe set is also communicated with the oxygen heat exchanger. An oxygen heat exchange tube group is mounted on the oxygen heat exchanger; the cold source pipe group is connected with the liquid air energy storage system; a cold source in the liquid-air energy storage system enters the nitrogen heat exchanger through the cold source pipe set for heat exchange and then returns to the liquid-air energy storage system. Through the arrangement of the liquid air energy storage system, the compressor can be driven by renewable energy electric energy or power grid night off-peak electricity to compress ambient air, independent liquid air is formed for energy storage, continuous operation can be achieved under the condition of unstable voltage, and the electric energy cost is reduced.

Description

Technical Field

[0001] This utility model relates to the field of external liquefaction technology, specifically to an external liquefaction device. Background Technology

[0002] External liquefaction refers to the process of separating air by using an external refrigeration system to provide the required low-temperature environment, thereby liquefying and separating oxygen and nitrogen in the air.

[0003] The external refrigeration system commonly used in existing external liquefaction devices is a mechanical compression refrigeration system. The compression process of a mechanical compression refrigeration system needs to overcome the interaction forces between refrigerant molecules and the frictional resistance inside the compressor, thus requiring a large amount of mechanical energy, which is mainly converted from electrical energy.

[0004] During operation, voltage instability in mechanical compression refrigeration systems can cause the ammeter pointer (digits) to fluctuate periodically or irregularly. This not only affects the normal operation of the refrigeration system but may also lead to motor overload or damage. Furthermore, to protect the motor, frequent starts should be avoided. Frequent starts cause a sudden increase in motor current, increasing the motor's load and potentially leading to overheating or damage. Therefore, mechanical compression refrigeration systems are highly dependent on the power grid, resulting in higher electricity costs.

[0005] Therefore, there is an urgent need to provide an external liquefaction device that is less dependent on the power grid and has lower electricity costs. Utility Model Content

[0006] The purpose of this invention is to propose an external liquefaction device that solves the problems of high dependence on the power grid and high grid costs in existing external liquefaction devices in the background art.

[0007] To achieve the above objectives, this utility model proposes an external liquefaction device, including a cold storage box and a liquid air energy storage system for generating liquid air. A nitrogen heat exchanger and an oxygen heat exchanger are installed inside the cold storage box. A cold source pipe assembly is installed on the nitrogen heat exchanger and connected to it. This nitrogen heat exchange pipe assembly is also connected to the oxygen heat exchanger, which is equipped with an oxygen heat exchange pipe assembly. The cold source pipe assembly is connected to the liquid air energy storage system. The cold source in the liquid air energy storage system enters the nitrogen heat exchanger through the cold source pipe assembly for heat exchange and then returns to the liquid air energy storage system.

[0008] Optionally, the cold source pipe assembly includes a cold source inlet pipe and a cold source return pipe. One end of the cold source inlet pipe is connected to the liquid air energy storage system, and the other end is connected to the cold source inlet end of the nitrogen heat exchanger. One end of the cold source return pipe is connected to the liquid air energy storage system, and the other end is connected to the cold source outlet end of the nitrogen heat exchanger.

[0009] Optionally, the nitrogen heat exchanger tube assembly includes a nitrogen inlet pipe and a first liquid nitrogen pipe connected at one end to the nitrogen heat exchanger, a liquid nitrogen inlet pipe at one end located at the cold source inlet of the oxygen heat exchanger, a second liquid nitrogen pipe located at the cold source outlet of the oxygen heat exchanger, and a first circulation pipe at one end located on the nitrogen heat exchanger; the other end of the liquid nitrogen inlet pipe is connected to the first liquid nitrogen pipe.

[0010] Optionally, a nitrogen compressor is provided on the nitrogen inlet pipe, and the nitrogen enters the nitrogen heat exchanger after passing through the nitrogen compressor; both the liquid nitrogen inlet pipe and the first liquid nitrogen pipe are provided with regulating valves, and the liquid nitrogen inlet pipe is connected to the first liquid nitrogen pipe.

[0011] Optionally, a second circulation pipe is connected to the second liquid nitrogen pipe; a first throttle valve is provided on the first circulation pipe, and the other end of the first circulation pipe is connected to the nitrogen inlet pipe.

[0012] Optionally, the nitrogen in the first circulation pipe passes through a nitrogen heat exchanger before entering the nitrogen inlet pipe; the connection between the first circulation pipe and the nitrogen inlet pipe is located at the inlet end of the nitrogen compressor.

[0013] Optionally, a second throttle valve is provided on the second circulation pipe, and the fluid in the second circulation pipe flows into the first circulation pipe after passing through the oxygen heat exchanger.

[0014] Optionally, the oxygen heat exchanger tube assembly includes an oxygen inlet pipe and a liquid oxygen outlet pipe connected to the oxygen heat exchanger.

[0015] Optionally, the liquid air energy storage system includes an air filter, an air compressor, a precooling device, a purification device, a circulating booster, an expander, and an air liquefaction unit connected in sequence. The air filter is equipped with an air inlet pipe, which is connected to the cold source return pipe, and the air liquefaction unit is connected to the cold source inlet pipe.

[0016] Optionally, the expander includes an expansion end and a booster end, the inlet of which is connected to the outlet of the circulating booster, and the outlet of which is connected to the inlet of the air liquefier; the outlet of the expansion end is connected to the inlet of the air liquefier.

[0017] Optionally, the air liquefaction unit includes a gas-liquid separation device connected to a purification device via a pipeline, a liquid-air storage tank connected to the gas-liquid separation device via a pipeline, a first air outlet connected to the inlet of a circulating booster, and a second air outlet connected to the inlet of an expansion end. The liquid-air storage tank is connected to a cold source inlet pipe, and a delivery pump is installed on the cold source inlet pipe.

[0018] Compared with the prior art, the present invention provides an external liquefaction device, which has the following beneficial effects:

[0019] This external liquefaction device, through the installation of a liquid-air energy storage system, can use renewable energy or off-peak electricity from the power grid at night to drive a compressor to compress ambient air, forming independent liquid-air for energy storage. It can operate continuously even when the voltage is unstable, reducing electricity costs. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the overall structure of the external liquefaction device of this utility model.

[0021] Figure 2 This is a schematic diagram of heat exchange inside the cold storage box of this utility model.

[0022] Figure 3 This is a schematic diagram of the liquid air energy storage system of this utility model.

[0023] The diagram shows: 1. Cold storage box; 2. Nitrogen heat exchanger; 3. Oxygen heat exchanger; 4. Cold source pipe assembly; 41. Cold source inlet pipe; 411. Transfer pump; 42. Cold source return pipe; 5. Nitrogen heat exchanger pipe assembly; 51. Nitrogen inlet pipe; 511. Nitrogen compressor; 52. First liquid nitrogen pipe; 53. Liquid nitrogen inlet pipe; 531. Regulating valve; 54. Second liquid nitrogen pipe; 541. Second circulation pipe; 542. Second throttle valve; 55. First circulation pipe; 551. First throttle valve. 6. Oxygen heat exchanger tube assembly; 61. Oxygen inlet pipe; 62. Liquid oxygen outlet pipe; 7. Liquid air storage system; 71. Air filter; 711. Air inlet pipe; 72. Air compressor; 73. Precooling device; 74. Purification device; 75. Circulating booster compressor; 76. Expander; 761. Expansion end; 762. Boosting end; 77. Air liquefaction unit; 771. Gas-liquid separation device; 772. Liquid air storage tank; 773. First outlet; 774. Second outlet. Detailed Implementation

[0024] The following detailed description, in conjunction with the accompanying drawings and specific embodiments, illustrates the present invention. Numerous specific details are set forth in the description below to provide a thorough understanding of the invention. However, the present invention can be implemented in many other ways different from those described herein, and those skilled in the art can make similar extensions without departing from the spirit of the invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0025] The external liquefaction device of this application can be applied to the external liquefaction of nitrogen, oxygen and other similar applications. The following is a detailed description of an external liquefaction device.

[0026] See appendix Figure 1 — Figure 3The diagram shows a preferred embodiment of an external liquefaction device according to this application. The external liquefaction device includes a cold storage box 1 and a liquid air energy storage system 7 for generating liquid air. A nitrogen heat exchanger 2 and an oxygen heat exchanger 3 are disposed within the cold storage box 1. A cold source pipe assembly 4 is installed on the nitrogen heat exchanger 2, and a nitrogen heat exchange pipe assembly 5 is connected to the nitrogen heat exchanger 2. The nitrogen heat exchange pipe assembly 5 is also connected to the oxygen heat exchanger 3, and an oxygen heat exchange pipe assembly 6 is installed on the oxygen heat exchanger 3. The cold source pipe assembly 4 is connected to the liquid air energy storage system 7. The liquid air cold source in the liquid air energy storage system 7 enters the nitrogen heat exchanger 2 through the cold source pipe assembly 4 for heat exchange, and then returns to the liquid air energy storage system 7.

[0027] This invention utilizes a liquid-air energy storage system 7 to generate liquid air from renewable energy or off-peak electricity from the grid, reducing the cost of generating a cold source and refrigeration. The cold-insulating box 1 controls the ambient temperature of the nitrogen heat exchanger 2 and the oxygen heat exchanger 3, preventing excessively high ambient temperatures from affecting heat exchange. This invention uses the liquid-air energy storage system 7 to compress air from renewable or off-peak electricity to form liquid air, which then directly exchanges heat with oxygen and nitrogen. This effectively reduces the dependence of the external liquefaction device on the power grid and lowers electricity costs, thereby reducing the production costs of liquid oxygen and liquid nitrogen. It should be noted that the nitrogen heat exchanger 2 has a gas-liquid separation function, which is existing technology and will not be elaborated upon here.

[0028] See appendix Figure 1 and Figure 2 As shown, in this utility model, the cold source pipe assembly 4 includes a cold source inlet pipe 41 and a cold source return pipe 42. One end of the cold source inlet pipe 41 is connected to the liquid air energy storage system 7, and the other end is connected to the cold source inlet end of the nitrogen heat exchanger 2. One end of the cold source return pipe 42 is connected to the liquid air energy storage system 7, and the other end is connected to the cold source outlet end of the nitrogen heat exchanger 2.

[0029] The cold source inlet pipe 41 is used to transport the liquid air generated by the liquid air energy storage system 7 to the nitrogen heat exchanger 2 for heat exchange to generate liquid nitrogen; the cold source return pipe 42 can return the heat-exchanged liquid or gaseous air back to the liquid air energy storage system 7, reducing the electrical energy required by the liquid air energy storage system 7.

[0030] See appendix Figure 1 and Figure 2 As shown, in this utility model, the nitrogen heat exchanger tube assembly 5 includes a nitrogen inlet pipe 51 and a first liquid nitrogen pipe 52 connected at one end to the nitrogen heat exchanger 2, a liquid nitrogen inlet pipe 53 with one end set at the cold source inlet end of the oxygen heat exchanger 3, a second liquid nitrogen pipe 54 set at the cold source outlet end of the oxygen heat exchanger 3, and a first circulation pipe 55 with one end set on the nitrogen heat exchanger 2; the other end of the liquid nitrogen inlet pipe 53 is connected to the first liquid nitrogen pipe 52.

[0031] This invention utilizes a nitrogen inlet pipe 51 to transport externally generated nitrogen into a nitrogen heat exchanger 2; a first liquid nitrogen pipe 52 to discharge the liquid nitrogen formed after heat exchange with liquid air; a liquid nitrogen inlet pipe 53 to transport the liquid nitrogen formed in the nitrogen heat exchanger 2 to an oxygen heat exchanger 3 as a heat source; a second liquid nitrogen pipe 54 to introduce a portion of the liquid nitrogen into the oxygen heat exchanger 3 for heat exchange and liquefaction of oxygen; and a first circulation pipe 55 to circulate the unliquefied nitrogen, repeating the liquefaction process to ensure that the obtained product is liquid nitrogen. This invention ensures effective liquefaction of both nitrogen and oxygen by first liquefying nitrogen with liquid air and then liquefying oxygen with nitrogen. Specifically, it first exchanges heat with nitrogen, which requires lower temperatures for liquefaction, and then uses liquid nitrogen to exchange heat with oxygen, guaranteeing effective oxygen heat exchange. It eliminates the need for circulating heat exchange with oxygen, requiring only circulating heat exchange with nitrogen, thus simplifying the entire device.

[0032] See appendix Figure 1 and Figure 2 As shown, in this utility model, a nitrogen compressor 511 is provided on the nitrogen inlet pipe 51, and nitrogen enters the nitrogen heat exchanger 2 after passing through the nitrogen compressor 511; both the liquid nitrogen inlet pipe 53 and the first liquid nitrogen pipe 52 are provided with regulating valves 531, and the liquid nitrogen inlet pipe 53 is connected to the first liquid nitrogen pipe 52; a second circulation pipe 541 is connected to the second liquid nitrogen pipe 54; a first throttle valve 551 is provided on the first circulation pipe 55, and the other end of the first circulation pipe 55 is connected to the nitrogen inlet pipe 51.

[0033] This invention utilizes a nitrogen compressor 511 to pressurize nitrogen, increasing its density and the number of nitrogen molecules per unit volume, thereby improving heat exchange efficiency. A regulating valve 531 controls the flow direction of liquid nitrogen after passing through the nitrogen heat exchanger 2, allowing for customization based on user needs. For example, when only liquid nitrogen is needed, the regulating valve 531 on the liquid nitrogen inlet pipe 53 can be closed, allowing all liquid nitrogen to flow out through the first liquid nitrogen pipe 52 for storage. When a large amount of liquid oxygen is required, the second liquid nitrogen pipe 52 can be used. The regulating valve 531 of the liquid nitrogen pipe 52 is closed, allowing all liquid nitrogen to flow into the liquid nitrogen inlet pipe 53 and enter the oxygen heat exchanger 3 for heat exchange to form liquid oxygen. The second circulation pipe 541 is used to pre-cool the nitrogen at the front end, reducing subsequent energy consumption and reducing the impact of thermal stress on the nitrogen compressor 511, thus extending the service life of the nitrogen compressor 511. The first throttle valve 551 is used to regulate the pressure of the high-pressure low-temperature nitrogen to form low-pressure low-temperature nitrogen, thus protecting the nitrogen compressor 511.

[0034] See appendix Figure 1 and Figure 2As shown, in this utility model, the nitrogen in the first circulation pipe 55 passes through the nitrogen heat exchanger 2 and then enters the nitrogen inlet pipe 51; the connection position between the first circulation pipe 55 and the nitrogen inlet pipe 51 is located at the inlet end of the nitrogen compressor 511.

[0035] This invention ensures that all nitrogen gas must pass through the nitrogen compressor 511 before entering the nitrogen heat exchanger 2 by limiting the connection position between the first circulation pipe 55 and the nitrogen inlet pipe 51, thereby guaranteeing the heat exchange effect. It should be noted that the first circulation pipe 55 is equipped with a one-way valve.

[0036] See appendix Figure 1 and Figure 2 As shown, in this utility model, a second throttle valve 542 is provided on the second circulation pipe 541, and the fluid in the second circulation pipe 541 flows into the first circulation pipe 55 after passing through the oxygen heat exchanger 3.

[0037] This invention, through the setting of the second circulation pipe 541, allows the fluid to pass through the oxygen heat exchanger 3 again for heat exchange to form nitrogen.

[0038] See appendix Figure 1 and Figure 2 As shown, in this utility model, the oxygen heat exchanger tube assembly 6 includes an oxygen inlet pipe 61 and a liquid oxygen outlet pipe 62 connected to the oxygen heat exchanger 3.

[0039] This utility model uses an oxygen inlet pipe 61 to input oxygen into an oxygen heat exchanger 3 for heat exchange; and uses a liquid oxygen outlet pipe 62 to export the liquid oxygen generated after heat exchange for storage. It should be noted that in this application, the first liquid nitrogen pipe 52 and the second liquid nitrogen pipe 54 are both connected to a liquid nitrogen storage tank, and the liquid oxygen outlet pipe 62 is connected to a liquid oxygen storage tank.

[0040] See appendix Figure 1 and Figure 3 As shown, in this utility model, the liquid-air energy storage system 7 includes an air filter 71, an air compressor 72, a precooling device 73, a purification device 74, a circulating booster 75, an expander 76, and an air liquefaction device 77 connected in sequence. The air filter 71 is provided with an air inlet pipe 711, which is connected to the cold source return pipe 42. The air liquefaction device 77 is connected to the cold source inlet pipe 41.

[0041] The expander 76 includes an expansion end 761 and a booster end 762. The inlet of the booster end 762 is connected to the outlet of the circulating booster 75, and the outlet of the booster end 762 is connected to the inlet of the air liquefaction unit 77. The outlet of the expansion end 761 is connected to the inlet of the air liquefaction unit 77. The air liquefaction unit 77 includes a gas-liquid separation device 771 connected to the purification device 74 via a pipeline, a liquid-air storage tank 772 connected to the gas-liquid separation device 771 via a pipeline, a first air outlet 773 connected to the inlet of the circulating booster 75, and a second air outlet 774 connected to the inlet of the expansion end 761. The liquid-air storage tank 772 is connected to the cold source inlet pipe 41, and a delivery pump 411 is installed on the cold source inlet pipe 41.

[0042] It should be noted that this application does not improve the liquid air energy storage system 7, which is existing technology and has been disclosed in the invention patent with application number 202411097195.6 entitled "Air Separation System and Air Separation Method". Of course, other similar liquid air energy storage systems can also be used.

[0043] See appendix Figure 1 — Figure 3 As shown, the usage process of this utility model is as follows:

[0044] Liquid air is formed in the liquid air storage tank 772 through the liquid air energy storage system 7, and then transported to the nitrogen heat exchanger 2 through the delivery pump 411. At the same time, the low-pressure nitrogen that needs to be liquefied enters the nitrogen heat exchanger 2 through the nitrogen inlet pipe 51 and the nitrogen compressor 511 to exchange heat and form liquid nitrogen and some cryogenic nitrogen. At this time, the liquid nitrogen flows out through the first liquid nitrogen pipe 52, while the cryogenic nitrogen enters the nitrogen inlet pipe 51 through the first circulation pipe 55 and the first throttle valve 551 to form cryogenic low-pressure nitrogen, and finally enters the nitrogen inlet pipe 51 again to circulate and exchange heat through the nitrogen compressor 511. The liquid nitrogen in the first liquid nitrogen pipe 52 can be adjusted according to the user's needs. Specifically, when only liquid nitrogen is needed, the regulating valve 531 on the liquid nitrogen inlet pipe 53 can be closed to allow all liquid nitrogen to flow out through the first liquid nitrogen pipe 52. When a large amount of liquid oxygen is needed, the regulating valve 531 on the first liquid nitrogen pipe 52 can be closed to allow all liquid nitrogen to enter the oxygen heat exchanger 3 through the liquid nitrogen inlet pipe 53 to exchange heat with oxygen, and then flow out through the second liquid nitrogen pipe 54. Some of the liquid nitrogen in the second liquid nitrogen pipe 54 will flow into the second circulation pipe 541, and then enter the oxygen heat exchanger 3 again through the second throttle valve 542 for heat exchange, and then enter the nitrogen inlet pipe 51 through the first circulation pipe 55.

[0045] The above embodiments are illustrative of this application and are not intended to limit this application. Any simple modifications to this application are within the protection scope of this application.

Claims

1. An external fluidization device, characterized by The application relates to a cold storage tank (1) and a liquid air energy storage system (7) for generating liquid air, a nitrogen heat exchanger (2) and an oxygen heat exchanger (3) arranged in the cold storage tank (1), a cold source pipe group (4) arranged on the nitrogen heat exchanger (2), a nitrogen heat exchange pipe group (5) connected with the nitrogen heat exchanger (2), the nitrogen heat exchange pipe group (5) also being communicated with the oxygen heat exchanger (3), and an oxygen heat exchange pipe group (6) arranged on the oxygen heat exchanger (3). The cold source pipe group (4) is connected with the liquid air energy storage system (7). The cold source in the liquid air energy storage system (7) enters the nitrogen heat exchanger (2) through the cold source pipe group (4) to perform heat exchange and then returns to the liquid air energy storage system (7).

2. The external fluidization device of claim 1, wherein The cold source pipe group (4) comprises a cold source inlet pipe (41) and a cold source return pipe (42), one end of the cold source inlet pipe (41) is connected with the liquid air energy storage system (7), the other end is connected with a cold source inlet end of the nitrogen heat exchanger (2), one end of the cold source return pipe (42) is connected with the liquid air energy storage system (7), and the other end is connected with a cold source outlet end of the nitrogen heat exchanger (2).

3. The external fluidization device of claim 1, wherein, The nitrogen heat exchange pipe group (5) comprises a nitrogen inlet pipe (51) connected with one end of the nitrogen heat exchanger (2), a first liquid nitrogen pipe (52), a liquid nitrogen inlet pipe (53) arranged on a cold source inlet end of the oxygen heat exchanger (3), a second liquid nitrogen pipe (54) arranged on a cold source outlet end of the oxygen heat exchanger (3), and a first circulating pipe (55) arranged on the nitrogen heat exchanger (2). The other end of the liquid nitrogen inlet pipe (53) is communicated with the first liquid nitrogen pipe (52).

4. The external fluidization device of claim 3, wherein A nitrogen compressor (511) is arranged on the nitrogen inlet pipe (51), and nitrogen enters the nitrogen heat exchanger (2) after passing through the nitrogen compressor (511). Adjusting valves (531) are arranged on the liquid nitrogen inlet pipe (53) and the first liquid nitrogen pipe (52), and the liquid nitrogen inlet pipe (53) is communicated with the first liquid nitrogen pipe (52). A second circulating pipe (541) is connected with the second liquid nitrogen pipe (54). A first throttling valve (551) is arranged on the first circulating pipe (55), and the other end of the first circulating pipe (55) is communicated with the nitrogen inlet pipe (51).

5. The external fluidization device of claim 4, wherein, Nitrogen in the first circulating pipe (55) enters the nitrogen inlet pipe (51) after passing through the nitrogen heat exchanger (2). The connection position of the first circulating pipe (55) and the nitrogen inlet pipe (51) is located at an air inlet end of the nitrogen compressor (511).

6. The external fluidization device of claim 4, wherein, A second throttling valve (542) is arranged on the second circulating pipe (541), and fluid in the second circulating pipe (541) flows into the first circulating pipe (55) after passing through the oxygen heat exchanger (3).

7. The external fluidization device of claim 1, wherein The oxygen heat exchange pipe group (6) comprises an oxygen inlet pipe (61) connected with the oxygen heat exchanger (3) and a liquid oxygen outlet pipe (62).

8. The external fluidization device of claim 2, wherein, The liquid air energy storage system (7) comprises an air filter (71), an air compressor (72), a pre-cooling device (73), a purification device (74), a circulating supercharger (75), an expander (76) and an air liquefier (77) connected in sequence, the air filter (71) is provided with an air inlet pipe (711) in communication with the cold source return pipe (42), and the air liquefier (77) is in communication with the cold source inlet pipe (41).

9. The external fluidization device of claim 8, wherein, The expander (76) comprises an expansion end (761) and a supercharging end (762), the inlet of the supercharging end (762) is in communication with the outlet of the circulating supercharger (75), and the outlet of the supercharging end (762) is in communication with the inlet of the air liquefier (77). The outlet of the expansion end (761) is in communication with the inlet of the air liquefier (77).

10. The external fluidization device of claim 9, wherein, The air liquefier (77) comprises a gas-liquid separation device (771) connected with the purification device (74) through a pipeline, a liquid air storage tank (772) in communication with the gas-liquid separation device (771) through a pipeline, a first gas outlet (773) in communication with the inlet of the circulating supercharger (75), and a second gas outlet (774) in communication with the inlet of the expansion end (761), the liquid air storage tank (772) is in communication with the cold source inlet pipe (41), and the cold source inlet pipe (41) is provided with a delivery pump (411).

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